콘크리트 鋪裝의 初期計測을 통한 初期擧動 特性分析

정원경,김동호,권혁찬,윤경구 강원대학교 산업기술연구소 2003 産業技術硏究 Vol.23 No.A

The purpose of this paper is to analysis of initial behavior of concrete pavement with initial measurement strain gauge for concrete pavement at field, and to investigate the field test results for field applicability testing. The early-age behaviors of concrete pavement slabs were measured using the strain gauges. From the slab depths and positions, the outputs from each gauges were recorded at initial curing period The initial measurement of concrete pavement and check of crack at the joint were performed. the results could be summarized as follows. From the results of concrete strength, compressive strength and flexural strength were showed 271kgf/㎝', 43kgf/㎝' respectively. From the tests of early-age strain measurement, it was found that the strain varied at the maximum value of 150μ ε and early1 behavior of concrete slab was showed a tensile strain However. for long-term was showed a compressive strain due to dry-shrinkage.

치과용 디지털 색상 분석용 기기의 정확성과 재현 능력에 대한 평가

정중재,박수정,조현구,황윤찬,오원만,황인남 大韓齒科保存學會 2008 Restorative Dentistry & Endodontics Vol.33 No.4

본 연구에서는 치과용 디지털 색상 분석기기 중 하나인 ShadeScan (CYNOVAD, Montreal, Canada)의 색상 분석의 정확성과 재현 능력을 평가하였다. 균일한 치아 배열을 가진 20대 성인 남자 8명과 여자 8명의 상악 인상을 고무인 상제 (Exaflex, GC, Japan)를 이용하여 채득하고, 인상에 A2 색상의 임시 크라운 제작용 자가중합형 레진을 주입하여 치아 모델을 완성하고, ShadeScan을 이용해 각 치아의 영상을 얻어 컴퓨터의 ShadeScan 프로그램으로 분석하였다. 그리고 측정 결과의 재현 능력를 평가하기 위해 2개의 치아 모델을 임의로 선택하여 각 치아마다 10회의 색상 측정을 시행하여 분석 결과를 비교하였다. 또한 분석된 영상의 동일 shade 간의 색차를 확인하기 위해 광중합 복합레진인 Gradia Direct (GC, Tokyo, Japan)와 shade guide의 CIE L^(*)a^(*)b^(*) 값을 백색과 흑색 배경판 상에서 spectrophotometer (Spectrolino, GretagMacbeth, USA)로 측정하고, ShadeScan에 의해 동일한 shade로 분석된 shade guide간의 색차를 계산하여 다음의 결과를 얻었다. 모든 치아에서 모델 제작 재료와 동일한 A2 색상므로 분석된 경우는 없었으며, 개개의 치아에서 전체 순면이 동일한 색상으로 분석된 예는 없었다. 또한 동일한 치아군에서 치아의 크기 , 형태 , 순면의 굴곡 등에 따라 서로 다른 색상 분포를 보였다. 재현성 평가에서 각 치아의 중앙부는 비교적 일정한 재현성출 보였으나, 절단부와 주변 부위는 재현성이 낮았으며, 동일한 shade로 분석된 shade guide 간에는 3 이상의 색차 (ΔE^(*))를 보였다. 이상의 결과는 치과용 디지털 색상 분석기기는 비록 높은 재현 능력은 가지고 있지만 정확성에 오류가 있음을 시사하며 , 따라서 이러한 기기를 이용한 색상 분석 시 좀 더 세밀한 주의와 다른 방법의 추가 사용이 필요하리라 사료된다. This study was done to evaluate the reliability of the digital color analysis system (ShadeScan, CYNOVAD, Montreal, Canada) for dentistry. Sixteen tooth models were made by injecting the A2 shade chemical cured resin for temporary crown into the impression acquired from 16 adults. Surfaces of the model teeth were polished with resin polishing cloth. The window of the ShadeScan handpiece was placed on the labial surface of tooth and tooth images were captured, and each tooth shade was analyzed with the ShadeScan software. Captured images were selected in groups, and compared one another. Two models were selected to evaluate repeatability of ShadeScan, and shade analysis was performed 10 times for each tooth. And, to ascertain the color difference of same shade code analyzed by ShadeScan, CIE L^(*)a^(*)b^(*)values of shade guide of Gradia Direct (GC, Tokyo, Japan) were measured on the white and black background using the Spectrolino (GretagMacbeth, USA), and Shade map of each shade guide was captured using the ShadeScan. There were no teeth that were analyzed as A2 shade and unique shade. And shade mapping analyses of the same tooth revealed similar shade and distribution except incisal third. Color difference (ΔE^(*)) among the Shade map which analyzed as same shade by ShadeScan were above 3. Within the limits of this study, digital color analysis instrument for dentistry has relatively high repeatability, but has controversial in accuracy.

VES-LMC 덧씌우기를 이용한 콘크리트 포장 보수

정원경,김용곤,김기헌,윤경구 강원대학교 산업기술연구소 2005 産業技術硏究 Vol.25 No.B

Since in 1970, the length of concrete pavements(JCP, JRCP and CRCP) are growing rapidly at both of main highways and local roads. Many of them are deteriorated and old enough to be repaired or replaced. The pavement is more important than the other infrastructures and it is very difficult to go around or block the traffic during the rehabilitation. The very-early strength latex-modified concrete(VES-LMC)may offer the advantages of high-early-strength, higher flexural strength, higher bond strength, and improved durability. The VES-LMC could be used at a kind of fast track ofr early opening to the traffic after 3 hours of concrete placement. The installation of VES-LMC overlay at Jung-Boo highway was successfully done from April 28 to 29, 2005. The traffic was closed at 07:00 PM and opened to traffic at 08:30 AM. The compressive and flexural strength of VES-MC were more than 28MPa, 6.2MPa after 4 hours, respectively.

Implementation of UPT Service in WIN-Based Mobile Communication Networks

Yun Won Chung(정윤원),Min Young Chung(정민영),Dan Keun Sung(성단근),In Jeong Kim(김인정),Jung Keun Shin(신정근),Sung Kim(김성) 한국통신학회 1999 한국통신학회 학술대회 및 강연회 Vol.1999 No.4

제2형 당뇨병 환자에서 Voglibose와 Acarbose의 비교임상연구

정인경,정재훈,민용기,이명식,이문규,김광원,정윤이,박중열,홍성관,이기업 대한당뇨병학회 2002 Diabetes and Metabolism Journal Vol.26 No.2

연구배경:아카보스와 보글리보스는 ­glucosidase inhibitors로써 비록 약리학적 작용이나 부작용에 있어서 두 약물간에 차이가 있다는 것은 잘 알려져 있으나 당뇨병 환자를 대상으로 아직 이에 대한 두 약물간에 직접적인 비교에 대해 연구된 바는 없었다. 이에 저자등은 국내 2형 당뇨병 환자에 대해 유효성과 부작용 발현에 대해 두 약제를 비교하고자 무작위법에 의한 위약 대조군의 이중 맹검법 연구를 시행하였다. 방법:시험 약제 투여 4주간의 관찰기를 설정하여 공복혈당의 변화가 30㎎/dL 이하이고, 식후 혈당이 200㎎/dL 이상인 환자로 기타 제외 기준에 해당하지 않은 환자 53명을 대상으로 하여 보글리보스 군(24명)과 아카보스 군(29명)으로 무작위로 나누었다. 치료기간은 총 8주로 하였으며, 4주간 간격으로 혈청학적 검사와 부작용을 분석하여 치료 효과가 부작용을 평가하였다. 결과:1)혈당 변화:보글리보스군은 식후 1시간 혈당이 치료 후 4주, 8주째 의미 있게 감소하였도, 아카보스군은 식후 1시간과 2시간 혈당이 치료 후 4주, 8주째 의미있게 감소하였다. 또한 관찰기 혈당에 대한 치료 4주째 감소량은 아카보스군에서 더 큰 경향을 보였으나, 치료 8주째에는 두 군 간의 강하정도에 의미있는 차이가 없었다(p=0.569). 2)인슐린 치의 변화:보글리스 군은 식후 1시간 인슐린 치가 치료 전에 비해 치료 4주, 8주째 감소하는 경향을 보였고, 공복 인슐린이나 식후 2시간 인슐린치는 치료전 후에 의미 있는 차이가 없었다. 아카보스군에서는 치료 전후로 공복 인슐린, 식후 1시간과 2시간 인슐린치에 의미 있는 차이를 보이지 않았다. 두약제 간에 치료 전과 치료 8주사이의 식후 2시간 인슐린의 감소량이 보글리보스 군에서 의미있게 높았다(p=0.040). 3)당화혈색소:보글리보스 군은 치료 전에 비해 치료후 당화혈색소가 감소하는 경향을 보였고, 아카보스군은 치료 전에 비해 의미있게 감소하였다. 당화혈색소 변화량은 두 군간에 의미 있는 차이는 없었다(p=0.412). 4)지질대사의 변화:중성지방, 콜레스테롤, 고밀도 진단백 콜레스테롤에 대해 두 군간에 의미 있는 차이는 없었다. 5)부작용:소화기계 부작용의 빈도는 치료 4주째 보글리보스 군에서 의미 있게 낮았으나(p=0.028), 치료 8주째 부작용의 빈도는 두 군간에 의미 있는 차이가 없었다(p=0.215). 결론:2형 당뇨병 환자에서 보글리보스와 아카보스의 두 약제의 임상적 유효성과 부작용발현에 대해 비교한 결과 치료 후 8 주 후 혈당강화효과는 두 약제간에 유사한 효과를 보였으나 보글리보스군에서 4주째의 초기 위장관 부작용이 적었다. Background : Acarbose and voglibose are alpha-glucosidase inhibitors. Although different pharmacological effects and adverse abdominal events associated with the two drugs have been reported, no study directly compared acarbose and voglibose in diabetes has been undertaken. To compare the pharmacological effects and gastrointestinal adverse events between two drugs, a randomized, placebo-controlled, double-bind study was performed in type 2 diabetes patients. Methods : The period of study was 12 weeks(observation period: 4 weeks; treatment period: 8 weeks). Fifty-three patients were randomized into two groups(the acarbose group: 24 patients; the voglibose group: 29 patients). The serum glucose, insulin, fructosamine, HbA_1c, cholesterol, triglyceride and the incidence of adverse events were measured. Results : 1) The reduction of glucose from before treatment to 4 weeks after treatment was significantly higher in the acarbose group, but the change before treatment and 8 weeks after treatment in the two groups was similar(p=0.569). 2) The insulin significantly decreased after voglibose treatment(p=0.040). 3) HbAa_1c level tended to decrease in voglibose group, and there was a significant decrease after acarbose treatment. However, the change in HbA_1c level before and after treatment was similar between the two groups(p=0.412). 4) The two drugs did not cause any other changes in the total, HDL-cholesterol and triglyceride. 5) The number of patients with gastrointestinal adverse events was significantly low 4 weeks after voglibose treatment (p=0.049), but the incidence in the two groups was similar after 8 weeks(p=0.215). Conclusions : Acarbose and voglibose significantly improved postprandial hyperglycemia in diabetes. The incidence of gastrointestinal adverse events was low 4 weeks after voglibose treatment(J Kor Diabetes 26:134~145, 2002).

자동차 허브 내·외경 측정 시스템 개발

윤규택,이동주,최만용,박해원,박정학 한국공작기계학회 2002 한국공작기계학회 춘계학술대회논문집 Vol.2002 No.-

An automobile hub is composed of a hollow cylindrical part with inner and outer diameters. These hub diameters must be precise, as any irregularities in them (diameters) can influence/degrade the motion of an automobile with this problem. Highly accurate and reliable hub inner and outer diameters measurement systems are therefore required for inspection of the diameters. In this research, an automobile hub inner and outer diameters measurement system has been developed and tested. The system consists of measuring heads with LVDT sensors, and associated software for automatic measurement and calibration of the diameters and the sensors respectively. The system has been evaluated in comparison with an existing measurement system, and the following outcomes have been achieved; ·Improved and guaranteed quality and reliability ·Increased productivity and cost reduction These results prove the system developed in this research to be suitable for automobile hub inspection.

수직 냉각면이 있는 정방형내 성층유체의 열적거동에 관한 실험적 연구

정현철,윤재원,장원택,전승배,이동석,김병철 朝鮮大學校 機械技術硏究所 2007 機械技術硏究 Vol.10 No.1

This study was investigated by experimentals on the thermal behavior of stratified fluids in the square cavity with the vertical cooling surface by variation of initial temperature and cooling surface temperature and concluded as follows: 1. When the cooling surface temperature of the square cavity was -4℃. the supercooling phenomena was occurred every times regardless initial temperature of fluids and when -6℃ freezing was begun with out supercooling phenomena. 2. The higher the initial temperature was, the longer supercooling phenomena duration was, and the longer the supercooling phnomena was, the higher the temperature of the upper fluids was. 3. When the supercooling phenomena of water was occurred, the rate of temperature decrease of silicon oil was higher and when there was no supercooling phenomena, it was almost same the rate of temperature decrease.

콘크리트 공극 분석을 위한 평면간격계수의 제안

정원경,최성용,김성환,윤경구 江原大學校 産業技術硏究所 2005 産業技術硏究 Vol.25 No.A

Air void systems in hardened concrete has an important influence on concrete durability such as freeze-thaw resistance, water permeability, surface scaling resistance. Linear traverse method and point count method described at ASTM are the routine analysis of the air void system that have been widely used to estimate the spacing factor in hardened concrete. Recently, many concretes often have a spacing factor higher than the generally accepted 200-250㎛ limit for the usual range of air contents. This study is proposed to estimate the plane spacing factor by calculation of simplicity. The plane spacing factor need two parameters that are air content and numbers of air voids in the hardened concrete. Those obtained from the standard air-void system analysis of the ASTM C 457. The equation is valid for all values of paste-to-air ratio because the estimation of paste content is unnecessary at the using ASTM C 457. The plane spacing factor yields a similar estimate of the standard spacing factor.

仁川海域 開發에 따른 潮汐變化 및 汚染物質 運送 豫測

鄭信澤,趙烘輦,蔡璋源 圓光大學校 環境建設硏究所 1997 環境建設論文集 Vol.6 No.-

Horizontal 2-D models which includes the wetting-drying treatment technique in the intertidal zone are established for the predietion of tidal changes and contaminant transport due to the development of Incheon coastal zone. Flow model is verified by the measurement data at Jeong-Do, and then the computed value is closely matched to the observed water elevation and velocity of main-flow direction. In the spring tide condition, pollutants transport pattern is simulated for the arbitrary pollutants loads. By the analysis of this numerical simulation results, pollutants are mainly transported by the advection along the narrow deep troughes. Thus, these models can be used as the compatible prediction model for the tidal change and pollutant transport due to the development plan of Incheon coastal zone.

장방형내 저온 단일 수평 원관 주위의 동결현상에 관한 실험적 연구

정현철,윤재원,장원택,전승배,이동석,김병철 朝鮮大學校 機械技術硏究所 2007 機械技術硏究 Vol.10 No.1

An experimental study on water in a rectangular cavity with a horizontal cooling tube was carried out to investigate the flow character and thermal behavior in the system. Each experiment was performed with variation of initial temperature and cooling tube temperature. When the cooling tube temperature was -4℃, the supercooling phenomenon was observed regardless of the initial water temperature. And the case of cooling tube temperature was -6℃ with initial temperature was below 4℃, the supercooling phenomenon was also observedin the large region of the test section. When the cooling tube temperature was -10℃, the local region of supercooling phenomenon was observed during the freezing process. And the higher initial temperature was, the higher supercooling degree and the less difference of the ice thickness between upward and downward was observed. It is shown that by controllingthe supercooling phenomena and the cooling tube temperature, it would lead to an increase efficiency of ice making.